Technical Field
The present disclosure relates to a motor drive circuit. More particularly, the present disclosure relates to a single phase DC motor drive circuit.
Description of Related Art
Typically, when starting a fan motor, if the fan is in a reverse direction due to the fact that the return wind in the system is too strong, an overcurrent situation is encountered and burns out inner elements of the fan because the motor cannot be brought back to the forward direction after being started and power accumulates. Therefore, determining whether a rotor of the motor is in the reverse direction and performing control correspondingly is an important issue in the field.
In the past, determining the rotation direction of a single phase DC motor was performed through two Hall elements located at different angles of the motor rotor and by utilizing the Hall Effect. By comparing the time sequences of the signals of the two Hall elements, the rotation direction could be determined. When using such a method to perform rotation direction determination, it is necessary to install at least two Hall elements in the DC motor, and a plurality of pins are also needed to connect the Hall elements in the control circuit. The design is both complicated and inconvenient.